Description: This Core provides access for Center investigators to state-of-the- art instrumentation for determination of macromolecular structure, small molecule crystallography, molecular modeling, study of transient kinetics and intermolecular interactions. The equipment includes an up-to-date X-ray diffractometer with an R-AXIS-IV image plate detector and cryogenic system for low temperature data collection supported by Silicon Graphics workstations for both data collection and data processing and appropriate software systems. A well outfitted Siemens P4 diffractometer is available for small molecule crystallography. Instrumentation for structural analysis also includes a 600 MHZ NMR spectrometer (Brucker) with a versatile collection of probes and SG1 workstation for data collection. Software packages for molecular mechanics and dynamics calculations and 3-D modeling are also available. Included in the instrumentation for structure determination are also a UV circular dichroism and Fourier transform IR spectrometers. Two IAsys instruments, one manual and one automated are available in the biosensor facility for study of intermolecular interactions. Transient kinetic studies can be carried out using a Dionex D-150 temperature jump system and two stopped-flow instruments. All necessary syringes and mixers are available to approach a dead time of 1 msec. Fluorescence emission, circular dichroism and absorbency can be measured independently or simultaneously. Fluorescence polarization can be measured and quence-flow studies can be carried out. Systems are temperature controlled and interfaced to computers for data acquisition and analysis. A spectrofluorometer capable of measuring fluorescence intensity excitation and emission spectra and fluorescence anisotrophy is included.